Electric snap switch



Feb. 6, 1951 A. KAsER 2,540,335

ELECTRIC SNAP SWITCH Filed Feb. 4, 1948 /N VE N TOR 141. BERT KASER Patented Feb. .6, 1951- ELECTRIC SNAP SWITCH Albert Kiser, Zug, Switzerland, assignor to Landis & Gyr, A. G., Zug, Switzerland. a body corporate of Switzerland Application February 4, ms, Serial No. 0,131 In Switzerland A ril 19,1939,

Section 1, Public Law 890, August 8, 1946 Patent expires April19, 1959 ZClaims. ((1200-67) The present invention relates to an improved electric switch of the type having a contact member which moves through a relatively short path of travel in actuation of the switch.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. 1

The invention consists in the novel parts, constructions, arrangements, combinations, and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

The present invention has for its object the provision of an electric switch of the type having a movable contact member which has a relatively short travel in which the contact tilts without the employment of a magnet and the movable, system for the contact has but two bearing points. Another obiect is the provision of such an improved 2 down and is provided the connection of a conductor. At the other end of the bar or strip 4 there is mounted an angle piece 8 longitudinally adjustable with respect thereto by means of screws 1.

Angle-shaped notches 9 and ID in the lug 5 and angle piece 8 respectively form bearing points for the movable system of the switch. This movable system itself consists of a leaf shaped tilting element lli2 of resilient, spring material, which comprises a portion ll stiffened by means of bent up flanges it along longitudinal edges thereof, and'a spring tongue II. This spring tongue is formed as a cut out part of and surrounded by the stiffened portion 1 I. By means of one end of the stiffened part I l and the free end of the spring tongue II, the tilting element is inserted between the bearing points 9- by proviously stressing the spring tongue.

so The stiffened part ll of the tilting element at the part thereof beyond the free end of the spring tongue I! bears the movable contact member ll of the switch and this, when the switch is opened, lies against an adjustable abutment l5, which is connected through an insulating block it to the switch in which the movable system bearing the movable contact consists of a single, integral element having a pair of rigidly arranged bearing points.

Of thedrawings: Fig. 1 is a side elevation, certain parts being shown in section, of an illustrative embodiment of installation for use in houses.

Of the immersion part of the thermostat there .is indicated a tube i and a rod 2, which two parts are made of materials of different coefficients of lexpansion, so that according to the temperature =conditions of the liquid to be heated there results .a relative movement between these two parts at the ends thereof shown in the drawing.

0n the tube I there is fixed, with the inter- ;positioning of an insulating plate 3, a bar or strip ,4 which has a lug 5 bent out of the central porbar or strip 4. The contact member ll lies onposite a fixed contact II, which is mounted by means of an insulating bush l8 in the bar or strip I and to which a second-conductor can be connected by means of a nut l9.

The rod 2 is formed at its upper end into an eye which surrounds the rod or strip 4 and the stifiened part of the leaf-shaped tilting element ll--l2 and by means of an adjustable insulating pin 2| forming the switch actuating means, rests against the part II near the bearing point III. II is an abutment, which prevents the pressing through of the tilting element "-42 up to the dead point.

The method. of operating of the above deof the toggle joint or reversible triangle of forces. It is to be assumed that on the. cooling of the liquid in the boiler below the set temperature the rod 2 falls. In such movement the insulat- 4 ing pin 20 presses on the tilting element Il-II. The latter by reason of its leaf shaped form and material is somewhat resilient notwithstanding the stiffening in the transverse direction, so that when the switch is opened there first. takes place a stressing of the stiffened part II. With further dropping of the rod 2 this stressing of the part I l increases until its force overcomes the force of the spring tongue I! and the triangle tiontbereofaudtbetreeendoiwhichisbentssaf forces formed betweentheboerlns p ints with a screw 8 serving for scribed switch is based on the lmown principle s,seo,sse

lll and the pressure point 01' the insulating pin it suddenly collapses, i. e-., the element ll-l! tilts and the movable contact member ll comes into engagement with the fixed contact H.

The abutment Ii preventing the pressing through of the tilting element ll-|2 up to the dead point thereof has the result that when the rod 2 by reason of the rising of the temperature in the boilermoves upwards, by the decrease in the pressure exerted by the insulating pin 29, the force of the spring tongue allows the tilting element to spring suddently back again, whereby the contact member II is dragged away from the part ll. 1

As can be clearly seen from the above description the switch according to the invention is of the greatest possible simplicity, since it has the minimum number of bearing points, which are theoretically necessary for switches having a tilting action, and since the movable system of the switch consists of a single piece, whereby the manufacture and assembly are simplified as compared with the known switches of this kind.

Instead-oi doing away with the elastic arrangement of the tilting element in operative combination with the insulating pin 2|, the latter can be elastically inserted in the eye-shaped part of the rod 2, so that when starting the switching motion this spring is at first stressed or released.

According to the exampleof construction the switch is assumed to be a single pole on-and-oi! switch. It can obviously also be made with a plurality of poles. The switch can also be made 3 as a change-over switch, in which case the abutsite to afnbntrolling pin likewise connected to the rod 3;; Inithis case the tilting element would thustiltover the dead point at each switching motion. i

The employment of the invention is in no way confined to an immersion thermostat, since the invention can be employed universally on electric switches, wheife it is desired to keep the travel of the movable contact small. It can also be employed in combination with a switch that remains in the closedposition after the being switched on and has-to be opened by hand. The fundamental arfangement of the parts; of the switch proper can. tljen be the same as in the example of construction, only instead of the abutment II a lever or the like must be provided, which, when actuated by hand, permits the return of the til ing element over the dead point.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom, within the scope of the accompanying claims, without departing from the principles of the invention and without sacrificing its chief advantases.

What is claimed is:

1. An electric switch comprising, in combination, a longitudinally extending strip element made of resilient material stiflened along the length thereof, a movable contact carried adjacent one end of said element, said element being formed with an integral, spring tongue portion having a free end toward said contact and intermediate the ends of said element, and a pair of fixed, opposed bearing points loosely engaging said free end of said tongue portion and the end of said element opposite said contact said element being in a condition of stress between said points.

2. An electric switch comprising, in combination, a longitudinally extending resilient strip element having stiffened longitudinal edges extending substantially the entire length of said element, a movable contact carried adjacent one end of said element, said element being formed with an integral, cut-out spring tongue portion having a free end toward said contact and intermediate the ends of said element, and a pair of fixed, opposed bearing points loosely engaging said free end of said tongue portion and the end of said element opposite said contact said element being in a condition of stress between said points.

- ALBERT KKSER.

REFERENCES CITED The following references are of record in the file of this patent: r

UNITED STATES PATENTS Number Name Date 1,215,665 Landis Feb. 13. 1917 1,622,721 Hook Mar. 29, 1927 1,694,569 Walsh Dec. 11, 1928 2,113,495 Richmond Apr. 5, 1938 2,198,428 Turner et a1 Apr. 23, 1940 2,343,060 Homing Feb. 29, 1944 FOREIGN PATENTS Number Country Date 551,851 Great Britain Mar. 12, 1943 

